Thermionic valve



Patented June 19, 1928.

CHESTER TIETIG, Ol' CINCINNATI, O HIO, ASSIGNOB CINCINNATI, OHIO.

PATENT OFFICE,

To .annua ma, or

vTHEBMIONIC VALVE.

Application led May 1,

This invention relates to improvements 1n thermionic-valves, and it hasfor one of its objects the substitution of more efficient generators ofthermions or electrons for the fila- I ments than have purpose in saidclass of valves.

The current capacity of a thermionicvalve has heretofore been small andthe limited emission of the customary filaments in l the valve has beenthe retarding factor in the desired development of large-sized valves ofhigh capacity.

Another important object of the invention herein is the substitution,for thc filament,

l5 of a so-callcd candle of burning metal, such candle, herein,consisting of a thin metal tube whose interior is packed with a granularor powdered metal mixture, such as aluminum, which is the metal to beburnt, and a. metallic oxide, such as iron oxide, the purpose of whichis to supply the required oxygen for the combustion of said metal. It isnot intended herein, however, to limit the invention to the above exactcombination of metal and metal oxides, norte having the metals in apowdered condition, or even inclosed in a tube, and the combustion mayalso be supported by some other element than oxygen with the metal,provided, of course, that incandescence is accomplished with dueemissions of thermions or electrons.

Therefore, by means of the combustion of a metal, there is produced amixture of incandescent metal and metallic oxides, which, it is wellknown, is a prolie source of elect-rons emitted into space.

As it is very important that a high vacuum be maintained inside thethermionicvalve, when the said` valve is used as a hard valve, that is,a very high vacuum valve, in contradistinction to a soft valve, onecontaining some gas, the following` precautions should be observed toinsure this condition (1) A vacuum-pump is operated continuously toexhaust the valve.

(2) The materials used for supporting combustion are duly freed fromoccluded gases and carbon before use. If the materials are packed into aso-called candle this may be exhausted of air and hermetically sealed.If the materials are used in loose powder form, the powder may behitherto been used for this b 1922. Serial No. 557,722.

passed through a num-chamber in' eluded gas.

(3) The grid and plate of the valve may e made of such metal as willabsorb or occlude gases.

In order to dispel or carry away the great amount of heat generated bythe combustion of the metal, the candle may be surrounded by acooling-jacket through which water or other cool liquid may becirculated.

preliminary vestibule vacorder to, free them of 0c In order to initiatethe combustion of the candle it 1s provided with two enamel-insulatedwires leading to its tip, where such Wlres are connected with a brldgecomposed of high-resistance wire. This bridge is made to glow by passingan electric current through it, and ignition of the material thenfollows. If the metal mixture is to be used 1n powdered form it may beignited by allowing itto fall to the bottom of the thermionic-valve boxwhich has already been heated to a degree of redness.

In order to preserve the proper spatial relation between the burningportion of the candle and the valve grid and plate a suitable stop maybe provided, and against which the burningr end of the candle may bcdriven. This stop may carry a shoe or the like made from tungsten orother high-melting metal, or metal oxide. Instead of said lstop,however. a clock-work mechanism may be used to feed the candle, in whichevent no stop is necessary. As a substitute or an alternative to thesaid clock-work it is obvious that a rubber-band or a spring may be usedin connection with a stop.

An obvious method of maintaining the op eration of the valve and thatwithout breaking the vacuum inside the valve, is to place a fresh candleon top of the one that is nearing complete consumption. The rubber bandis lifted to the top of the fresh candle so as to drive it. Sinceplacing the stub of an old candle on the top of a new one, or viceversa, is as old as the use of candles, this method is consideredobvious and is not claimed as a part of the invention.

A modified form of the apparatus herein will be found in the followingstructure:

A thermit-candle of small diameter and great length is prepared bydrawing down Such a candle of larger diameter. The

y of a. cylindrical* metallic section made smaller diameter candle isflexible so that, therefore, it is used, wound on a drum, the latter andthe candle being contained or housed in their entirety, with the feedingmechanism, which may be clock-work, a solenoid, or an electric motorwithin the valve case. The candle is fed, in this form, from they drumby such mechanism into the central area of the grid-coil.

A bowl or catch-all may be conveniently placed under the candle in thevalve-casing for the express purpose of catching the hot metal drippingstherefrom.

The accompanyingr drawing is a diagrammatic view, showing thevalve-casing 1n block-section and all the parts of the device comprisingmy invention within said valvecasing, some of them being in dotted linesand some being extended from the casing in assembled relation as well asin initial p0- sition ready :for operation and use.

In said view- A indicates the casing or inclosing bodyportion of thedevice, which is composed of iron, brass, glass. or other suitablematerial and it must be absolutely air-tight.

B indicates the thermitcandle, and C, a surrounding, concentric,water-cooling jacket for the candle, the latter extending a little abovethe jacket. The jacket is provided with awater inlet-pipe D and anoutlet-pipe E for the candle.

A mechanically-strong rod or strip F serves as a stop for the candle and1t must be of insulating material for at least a portion of its length.The candle and stop-rod extend parallel to each other a short distanceabove the top of the casing and the lower end of the said stop-rod -isconnected .by means of a U-shape lateral extension G with the lower 'endof the candle. The stop-rod and its lower lat-eral extension are made ofa high-melting metal, or a' refractory metal oxide such as magnesiumoxide.

Suitable mercury-seals H and H are provided near the top of thewater-.jacket C and that of the said stop-rod F, respectively, toprevent air leaking intothe valve.

Set-screws I, I, are provided on the mercury-seal H to adjust thestop-rod F for the candle. Y

A pipe J leads from the lower part of the casing to a.V vacuum-pump (notshown), the latter being'r operated continuously whlle the valve hereinis in action. -Y

A bowl K,Ymade of a refractory material, is provided'beneath the lowerVend of thecandle tol catch any molten 'metal drlpplngs from the candlen'use. A'

L indicates the plate, which is in the form from high-melting metal,and' M indicates the grid` bothwlocated at theA lower end of the candle,saidggrid 'and the v.greater lportlon of the candle .beingjsrhown indotted lines which is deemed quite sufiicient to indicate their positionand structure.

N N, indicate a pair of wire-connections leading to the grid, and 0, O,a similar'pair of wire-connections leading to the plate, both pairs ofwires being insulated from the val vt casing. i

P` P, 4indicate a pair of wire-connections leading to the tipofthecandle, where is 1ocatcd a resistance-wire that is arranged tocross or span said wire-connections I, P. rlhe candle is ignited bymeans of an electric current sent across said resistance-Wire.

Q represents a rubber-band or rubber strip stretched from the oppositesides of the casing across the top of the candle to act as a drivingmeans to force or keep the lower end of the candle into contact with thelonger u turned end G of the stop-rod extension x. vSuitable lugs R, R,extend laterally from the upper part of the valve casing for theengagement of the opposite ends of the said rubber-strip Q. inrfastening the latter in strained or stretched relation 'with the topVof the candle.

In summing up the ad\f'antages of my improvements herein I callparticular attention to the following The basic idea or principle ofproducing electrons in unlimited or large quantities by the chemicalcombustion of metals, instead of, as heretofore, by heating a.filaments; the great advantage of having y electrons produced in saidlarge quantities upon which the increased capacity of any thermiomcvalvelargely depends; `the basic ideal or principle ot having metal oxidesproduced in a state of incandescence. metal oxides being so much betteras emitters of electrons -V Y than the metals themselves the effect iswell known as the lVehnelt effect and the in? Vention herein offersmeans vof gettingthe desired benefit of said effectl without recourse toan oxide-coated filament such as in general use; the decided advantageof elimi-y nating the gas from the thermionic-valve al'- though 1t is tobe understood that it'vwill function for most purposes in the presence Yi i of gas or vapor, such operation being probably ionic instead ofelectronic; the further advantage of providing means for vpr'oducingelectrons or thermions at a place where they may be utilized inthe'customary way by arrangements well known in this particular art; thefurther advantage that the materials used for combustion do notnecessarily have to be confined in a tube, but that they may beotherwise utilizedfin theforln of a powder that is introducedthrough thei 125 wall ofthe thermionic-valve from an auxiliary vacuum-chamber, orfed through the said tube by meansof a screw-conveym'; the readysubstitution orL replacing of va. candle when required, afterconsumption or otherwise; and, furthermore, thatV the composi-`objectionable under certain conditions and uses of the valve would beproduced by the combustion, which, under ideal conditions, does notproduce gas.

It is to be understood that the invention herein is not confined to anysingle theoretical way in which a thermionic valve may operate. All theways in which such valves may operate is at present a matter ofconsiderable obscurity and the theory of operation of even the wellknown forms cannot yet be said to-have been positively proven. It is notreally known how far ions are responsible for what takes place orwhether the phenomena are produced only by electrons. Therefore I cannotand will not state at this time that only electrons or only ions areproduced, or that a mixture of them is produced. There is even confusionamong scientists as to Where the identity of an elec tron stops and theidentity of an ion begins.

I claim 1. In a thermionic valve, the method of operating said valve byproducing carriers of electric charges in said valve by conductingachemical reaction therein.

2. In a thermionic valve, the method of operating said valve b producinthermions in said valve by con ucting a c iemical reaction therein.

3. In a thermionic valve, a candle which is a generator' of electriccharges, means for positively feeding said candle into a positionwherein the ignited end of said candle may generate carriers of electriccharges so that they may be eiiiciently acted upon by an electricalfield surrounding said candle and meansfor stopping and regulating saidcandle in such correct position.

4. In a thermionic valve, a thermit candle, cooling means surroundingsaid thermit candle, feeding means and stopping means for said thermitcandle whereby said candle is fed into the zone of greatestelectricalintensity of said valve and maintained in such position. Y

5. A thermionic-valve having means for generating carriers of electriccharges by chemical combustion.

6. In a thermionic-valve, a tubular thermit-candle, a tubular watercooling-jacket surrounding said candle, means for supplying and drainingsaid water cooling-jacket, means for positively feeding said candle intoaction, `rstop means for controlling the feed of said candle, means formaintainingy a vacuum in the valve casing, means for supplying elect-riccurrent to the. valve, sealing means to prevent air leaking into thevalve, a grid and a cylindrical plate, said grid and plate beingarranged in operative relation with the lower end of said candle.

7. The process of producing carriers of electric charges in athermionic-valve by combusting a metal therein.

8. The method of producing thermions in a thermionic-valve to operatethe valve, which consists of combusting ametal therein.

9. The method of generating carriers of electrical charges in athermionic-valve by bringing into electrical infiuence with the plateand grid members of said valve and their associated structure, a mass ofincandescent, molten material, Said material being a known generator ofelectrical charges when so molten.

CHESTER TIETIG.

